Subband structures of GaAs/AlxGa1-xAs multiple quantum wells.
Explore the source record for details and available documents.
Biomedical subjects
Publications and source records attributed to Y Fu.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
A new microcatheter system was used for diagnostic and therapeutic purposes in three cases of arteriovenous malformation. This microcatheter is used with a steerable guidewire and provides high selectivity of the target vessels and greater catheter maneuverability than does balloon catheters. Tissue adhesive was safely injected for the therapeutic embolization in two of the cases. With this system, however, the utmost attention is necessary to prevent reflux of the tissue adhesive and to avoid lacerating the feeding vessels with the guidewire. This microcatheter system was found to be very useful for diagnostic and therapeutic procedures in endovascular treatment of cerebral arteriovenous malformations.
To evaluate the usefulness of magnetic resonance (MR) imaging of intracavernous pathology, T1-weighted spin echo images of four vascular lesions and 10 neoplastic lesions with surgically confirmed cavernous sinus (CS) invasion were reviewed retrospectively. In one case of traumatic carotid-cavernous fistula (CCF) and one of dural arteriovenous malformation (AVM), the internal carotid artery (ICA) and rapid shunted flow were depicted as signal voids, and the relationship between the ICA and shunted flow was clearly shown. Normal venous flow appeared as a low-intensity area and was observed even in the presence of the CCF and dural AVM. In two cases of thrombosed aneurysms, the thrombosis was clearly demonstrated, along with patent arterial flow in one case; in the other case, however, it was impossible to differentiate patent arterial flow from calcification. The intensity of all neoplastic lesions was similar to that of the cerebral cortex. The relationship between the ICA and the tumors was clearly demonstrated. The visual pathways were also plainly shown unless they were involved, or markedly compressed, by tumor. CS invasion was strongly associated with four findings: 1) encasement of the ICA by the tumor; 2) marked displacement of the ICA; 3) absence of low intensity, which reflects normal venous flow, in the CS; and 4) extension of extrasellar tumors to the medial wall or of intrasellar tumors to the lateral wall. MR imaging was judged promising in the evaluation of intracavernous pathology.
Explore the source record for details and available documents.
Embryos from a female of Xenopus laevis (designated as no. 65) arrest development at gastrulation and are assumed to be ova-deficient mutant. We dissociated these embryos and studied RNA synthesis at different stages. The cells from the ova-deficient embryos reaggregated quite actively as wild-type embryo cells until the late gastrula stage. RNA synthesis was normal at the early blastula stage but greatly inhibited by the late blastula (stage 9.5) stage, when the synthesis of DNA and protein was still not inhibited appreciably. Thus, inhibition in RNA synthesis appears to be the first manifestation of the maternal defect that occurs before the gastrulation arrest.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
1168 patients with primary carcinoma of lung had been treated by surgery in our hospital from 1976 to 1985. Among these patients we found 7 patients with second primary lung cancer. The incidence is 0.6% in this series. The criteria of the second primary lung cancer are: different histological type; synchronous lesion located in the contralateral lung or in different lobes or segments of the ipsilateral lung which must all be stage I; or prolonged interval between the initial and second resection (metachronous lesions), but the initial lesion must be proved as stage I. Lobectomy was the most common procedure for the initial and second resections. The result of the treatment was satisfactory with one patients surviving 6 years and 6 months. There was no operative mortality or complications. We consider that careful diagnosis is important and continued follow-up is necessary for all bronchogenic carcinomas.
Explore the source record for details and available documents.
Processing of 40 S pre-rRNA into 18 and 28 S mature rRNAs was studied in Xenopus embryonic cells by pulse-chase experiments using actinomycin D as a transcription-inhibitor. Gel electrophoretic analyses revealed that the rate of processing was accelerated due to a shortening of the half-life of 40 S pre-rRNA from 19 min at the gastrula stage to 9 min at and after the neurula stage. The step under developmental control appeared to be the cleavage of 40 S pre-rRNA into 18 S rRNA and the 34 S rRNA intermediate, since the time interval between the first detection of labeled 40 S pre-rRNA and 18 S rRNA was significantly shortened as development proceeded.
Tissues from two cases of bowenoid papulosis of the vulva with coexistent invasive squamous cell carcinoma were evaluated for the presence of human papillomaviruses (HPVs) and for nuclear DNA content. In both cases, HPV type 16 and nuclear aneuploidy were found in bowenoid papulosis as well as in invasive carcinoma. Patterns of hybridization suggested that the viral genome was integrated into the cellular genome in both bowenoid papulosis tissues as well as in invasive carcinoma tissues. These observations suggest that lesions designated as bowenoid papulosis may have invasive cancer potential. The term vulvar intraepithelial neoplasia seems to be more appropriate for HPV-16-containing aneuploid, intraepithelial lesions of the vulva.
Explore the source record for details and available documents.
Monolayer cultures of JU56 wallaby cells were exposed to germicidal U.V. and/or photoreactivating (PR) light. The U.V. exposures induced dose-dependent cell-death. The survival data are consistent with a common extrapolation number (n) of 6 x 17 +/- 0 x 98 with a D(0) of 123 x 0 +/- 6 x 8 erg/mm2 for photo-reactivated cells and a D0 of 87 x 3 +/- 4 x 9 erg/mm2 for non-photoreactivated cells; the photoreactivation protected the cells with a dose-modification factor of 1 x 41 +/- 0 x 02. Therefore PR is not a shoulder phenomenon and so has no relationship to the repair of sub-lethal damage.
The present study reports unusual, long, tubular, rod-shaped cytoplasmic inclusions found in the stromal cells of a cerebellar hemangioblastoma, associated with von Hippel-Lindau syndrome. These inclusions have two layers of circular, laminated filaments, and longitudinally arranged filaments; and appear similar to the so-called "Hirano bodies", which have been previously found in normal and various pathologic conditions of the brain tissue, skeletal muscle cells in myopathy, and interstitial cells of the testis. A review of previous ultrastructural studies of cerebellar hemangioblastoma shows several different types of cytoplasmic inclusions, but none are found to be identical to the present report.
A case of a functioning interstitial-cell tumor in a 12-year-old Negro boy is reported. The patient manifested precocious puberty, with signs of sexually aggressive behavior. The ultra-structural studies of the tumor showed features similar to those of the few cases previously reported in the literature. One characteristic finding was the presence of numerous membranous whorls within the cytoplasm. The cells grown in tissue culture were maintained for at least 9 weeks and were confirmed as testicular interstitial cells. Ultrastructurally they were similar to the cells in vivo, as evidenced by the finding of cytoplasmic organelles related to steroid synthesis.
The electron microscopic features of a leiomyosarcoma occurring in the lung, a rare site, were studied; Unusual was the fwnding of extremely electron-dense bands that interrupted the longitudinally-arranged microfilaments and dense bodies of many of the tumor cells. These bands superficially resembled anomalous Z-bands seen in nemalin myopathy and aging rat cardiac muscle, but have not been described to occur in smooth muscle tumors. They are thought to represent condensations of dense bodies in degenerating tumor cells.